This CL adds an IsTemplateForApiObject method to FunctionTemplate
allowing the embedder to check whether a given API object was
instantiated by this template without including parent templates
in the search. It also replaces the v8::ApiObject in the fast API
with a raw v8::Value pointer to allow use of standard C++ casts.

Bug: chromium:1052746
Change-Id: I0812ec8b4daaa5f5005aabf10b63e1e84e0b8f03
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2595310
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73999}